Design Assignment - Overview and Explanation

Individually, or in groups of no more than three students, you are to design a radiator for a deep-space spacecraft that satisfies the customer design requirements listed below. For the radiator to be feasible, it must meet the requirements. The radiator is a component of an active cooling system that employs an anhydrous ammonia pumped fluid loop to remove thermal energy from the spacecraft and transport it to the radiator inlet. After flowing through the radiator, the cooled ammonia returns to the spacecraft and the cycle repeats. Also provided below is a list of customer "desirements" giving additional attributes (somewhat more vague) that are highly desirable, but not mandatory. The best design will meet all of the requirements and address all of the desirements that do not put unacceptable burden on the design. (The degree of unacceptability is dependent on the overall design solution and will vary depending on the design solution chosen.)

Engineering design is inherently a creative process where several unknowns exist and can be traded against each other to achieve an acceptable solution to the problem. Designers need to understand customer needs to arrive at acceptable solutions. Designers should work with customers to define clear, concise, and complete requirements sets at the beginning of a project, but designers must also expect to encounter additional questions that need to be coordinated with the customer to ensure the customer's needs and objectives are met by the design solution. This means communication between the design team and the customer is essential throughout the process but especially during the early phases of design. For the class design project, the instructor will serve as the customer. Any questions you have about the applicability or interpretation of requirements should be directed to the instructor in writing (preferably by e-mail).

As noted in the course syllabus, work on the design project will be performed outside of class time. It is expected that the student(s) will use thermal design concepts, analyses and tools introduced and developed in the course, but additional research and study of material outside the normal Heat Transfer Course scope will be required to create an outstanding design solution. The integration and use of other mechanical engineering concepts, analyses and tools (e.g., fluid-flow analyses, structural analyses, materials evaluations, etc.) are strongly encouraged to make the design project the most beneficial to the student's learning experience. (Try applying what you've learned in other courses. You should have fun with this!)

Reporting

The design solution must be communicated to the customer in both a written report and an oral presentation. The written report is due Friday, December 5th at the beginning of class. The oral presentations will be given to the class on Monday and Wednesday, December 7th and 9th. (Presentation order will be determined at a later date.) The report outline is as follows:

Title Page
Executive Summary (one page maximum) Table of Contents
Design problem statement
- Include design requirements Detailed design documentation including:
- Description of the design concept and configuration
- Results of analyses and trade studies
- Drawings
- A detailed parts list (identify material and mass of each part) Conclusions
References Appendices (if needed)

The oral presentation should be a five-minute summary of the design concept description and your conclusions.

Customer Design Requirements

Ammonia flow rate into radiator: 0.05 kg/s Ammonia inlet temperature: 12.7 ºC Ammonia inlet pressure: 2.0 MPa Ammonia exit temperature: -40 ºC

Presents only controllable safety hazards during build, assembly, and processing

Customer Design "Desirements"

Minimized mass Minimized stowed volume
Maximized manufacturability Minimized cost
Minimized time to delivery
10-year or greater operational life
0.2 MPa maximum NH3 pressure drop (inlet-to-outlet)